1. Technical Field
The present invention relates to a method of high pressure die casting in a first metal alloy reinforcements for main bearing scantlings in a second metal alloy block for an internal combustion engine.
2. Background
Engine blocks cast of a light alloy such as aluminum alloy have the primary advantage that they are light in comparison with cast iron alloy engine blocks, thereby offering the opportunity to achieve high power/weight ratios in the engine. They, however, have the disadvantage that they are not as strong as iron alloy engine blocks and are not as well able to withstand the stresses encountered in engine operation. Particularly the scantlings in the engine, which provide support for the main bearings, are subject to high stresses.
It is previously known to increase the strength of the scantlings in an aluminum alloy engine block by casting an iron core reinforcement in the aluminum material of each scantling. Such a reinforcement forms a semi-circular surface facing the main bearing. According to a previously known method (U.S. Pat. No. 4,643,145) the reinforcements for the scantlings are positioned in the engine block die by means of rods which are screwed into the bores for the main bearing screws. The die is then gravity filled with molten aluminum alloy to cast the block around the reinforcements. After solidification the casting is removed from the die and the rods removed from the reinforcements.